1. Field of the Invention
The present invention relates to a method of inducing osteogenesis, in particularly to a method of inducing bone-forming and promoting osseointegration around a titanium implant surface.
2. The Prior Arts
The osteoconduction of a bone graft indicates that the bone graft is provided as a support in a bone defect area, and osteoprogenitor cells are allowed to scramble on the graft and then converted via proliferation and differentiation into osteoblast cells by which the osteogenesis can take place, whereas the osteoinduction means that the bone graft is able to induce mesenchymal cells around it or bone marrow stem cells from the blood to differentiate into osteoprogenitor cells.
The best material for a bone graft is an autologous bone graft that is obtained from the own body, the advantages of which include that cell activity may last during its implantation and there is no problem with disease infection. However, due to limited available quantities of the autologous bone grafts as well as possible pains and bleeding after operation, researchers sought for years to find an another excellent bone graft to recover its defects. In this regard, it is proposed to implant an improved demineralized bovine bone graft into murine muscles to induce osteogenesis. Afterwards, a number of studies are focused on the application of demineralized freeze-dried bone allografts in the treatment of periodontal defect and results from the studies also demonstrate it exactly has an effect of promoting bone formation.
Demineralized freeze-dried bone allografts can be employed in the treatment of bone defects to promote the bone formation, but they may contain proteins remaining in the bone grafts, the proteins can become antigens of an immune response, and can be contaminated by microorganisms, for example, mad cow disease. Therefore, it is of great importance to find a substitute that can be used to replace allografts to induce osteogenesis and therefore treat the bone defects.
It is known that chitosan is an essential complicated polysaccharide that is obtained by deacetylating chitin at high temperature and in the concentrated acidic and basic solutions. Chitin is a naturally occurring polysaccharide next to cellulose and widely spread in animals and plants. Previous studies have shown that chitosan can be used to promote cells to adhere and grow, or used as carrier of delivering drugs. However, as a result of extraordinarily rapid degradation and high expansion rate of chitosan membrane, a short life span is the problem of the wrapping material out of chitosan membrane.